U

Ul
Underwriters' Laboratories, Inc.

Ultimate Gas Usage
Identifies the ultimate use of the gas that is sold to the final user; e.g., electrical generation; commercial use.

Ultimate Limit State
Function of design variables which defines the resistance of a member to failure; i.e., its maximum load carrying capacity at failure.

Ultimate Recovery
The quantity of oil or gas that a field, or a property will produce.

Ultrasonic
Pertaining to mechanical vibrations having a frequency greater than approximately 20,000 Hz.

Ultrasonic Absorption
A dampening of ultrasonic vibrations that occurs when the wave transverses a medium.

Ultrasonic Dead Zone
The distance from the front surface of the pipe to nearest inspectable depth.

Ultrasonic Inspection
An examination of materials and fabrication using pulse echo ultrasonic equipment for the purpose of locating and sizing discontinuities in the welds and reporting such findings for evaluation of compliance with the acceptance criteria.

Ultrasonic Inspection Procedure
The detailed written procedure outlining the specific ultrasonic inspection techniques and criteria to be utilized during the construction of a particular platform.

Ultrasonic Penetration
Propagation of ultrasonic energy through an article.

Ultrasonic Presentation
The method used to show ultrasonic wave information. This may include A, B, or C scans displayed on various types of recorders or cathode ray tube instruments.

Ultrasonic Range
The maximum ultrasonic path length that can be displayed. Also referred to as: Ultrasonic Sweep.

Ultrasonic Resolving Power
The measure of the capability of an ultrasonic system to separate in time two discontinuities at slightly different distances.

Ultrasonic Spectrum
The frequency span of elastic waves greater than the highest audible frequency, generally regarded as being higher than 2.0 x 10(to the 4th power) cycles per second (Cps), to approximately 10(to the 9th power) Cps.

Ultrasonic Test Surface
That surface of a part through which the ultrasonic energy enters or leaves the part.

Ultrasonic Testing
A nondestructive method of inspecting materials by the use of high frequency sound waves.

Ultrasonic Velocity
The speed at which sound waves travel through a medium.

Ultraviolet Light
Light waves shorter than the visible blue-violet waves of the spectrum. Crude oil, colored distillates, residuum, a few drilling fluid additives, and certain minerals and chemicals fluoresce in the presence of ultraviolet light. These substances, when present in drilling fluid, may cause the fluid to fluoresce.

Umbrella Discharge
SEE: Spray Discharge.

Unallocated Basis Code
An indicator of the basis by which unallocated wells are determined.

Unconformity
The surface of contact between rock units at which is indicate a substantial nonstructural break or gap in the stratigraphic record. At the unconformity, the stratigraphically older rock unit is not succeeded by the next younger unit in the expected stratigraphic sequence. Such breaks are usually indications of extensive periods of erosion, with loss of the intervening rock record. An unconformity can also be formed by an extended period of nondeposition.

Unconformity Stratigraphic Unit Name
Name of the stratigraphic unit representing an unconformity.

Unconformity Type
The type of unconformity surface; e.g., angular unconformity; disconformity; paraconformity.

Uncontrolled Sidetrack
The sidetracking of a wellbore where direction is unimportant and not controlled.

Underbalance
The condition in the borehole wherein the weight of the drilling fluid exerts a pressure less than the pressure of the fluids in the rocks being drilled. In a condition of underbalance, fluids from the surrounding rocks enter the borehole.

Undercut
Under cutting on submerged arc welded pipe is the reduction in thickness of the pipe wall adjacent to the weld where it is fused to the surface of the pipe.

Underfill
Formed during bar rolling when the bar does not completely fill the rolling die. Also formed during rod end forging when there is insufficient material to fill the die.

Underflow
The discharge stream from centrifugal separators.

Underflow Header
A pipe, tube, or conduit into which two or more hydrocyclones discharge their underflow.

Underflow Manifold
An arrangement by which the underflow from one or more hydrocyclones or from one or more underflow headers can be diverted.

Underflow Opening
The actual opening through which the underflow leaves the centrifugal separator.

Underground Blowout
An uncontrolled flow of wellbore fluids and/or reservoir fluids into lower pressured subsurface zones.

Underground Injection Control Agency Application Date The Date The Operator Submits An Application For An Underground Injection Control Permit.

Underground Injection Control Permit Approval Date The Date A Regulatory Agency Approves An Operator's Underground Injection Control Permit.

Underground Injection Control Permit Number
The number assigned by a regulatory agency to an underground injection control permit.

Underground Storage Well
A well used for for temporary storage of fluids in artificial or natural caverns or reservoirs.

Underpressure
Pressure in a process component less than the design collapse pressure.

Underream
To enlarge a borehole below the casing.

Underreamer
An item of equipment which can enlarge an existing hole. Unlike a reamer, the arms on which the cutting structure is mounted are retractable. It can thererfore be passed through a small diameter restriction before the arms are extended and underreaming operations begin.

Undersaturated Fluid
A liquid capable of holding additional gaseous components in solution or a vapor capable of holding additional liquid components in solution at the specified pressure and temperature.

Undersize
Material consisting of particles smaller than a specified aperture.

Underwater Completion Count
The number of underwater completions that have their production processed at this location.

Underwater Safety Valve
An automatic valve assembly (installed at an underwater wellhead location) which will close upon loss of power supply. Commonly abbreviated as: USV.

Undesirable Event
An adverse occurrence or situation in a process component or process station which poses a threat to safety; e.g., overpressure; underpressure; liquid overflow.

Undeveloped Gross Acres
The sum of all undeveloped tract gross acres on a lease. Contains the total number of acres covered by the legal description of the entity in which it is included.

Undeveloped Leasehold Type
Indicates the type of undeveloped leaseholds that are dedicated under a contract.

Undeveloped Net Acres
The sum of all undeveloped tract net acres on a lease. Contains the total number of net acres covered by the legal description of the entity in which it is included.

Undivided Agreement
A type of operating agreement that fixes the sharing of costs and benefits for the life of the unit.

Unencumbered Federal Ocs Area
The surface area under the jurisdiction of the United States government which is not encumbered by fact of being disputed, deferred, withdrawn, or designated as Section 6, 7, or 8 of the Outer Continental Shelf Lands Act, as amended.

Unfired Process Area
That area that contains process equipment that does not have a flame.

Uniformitarianism
The geologic principle that past geologic events can be explained by phenomena and forces observable today.

Uniformity Coefficient
The ratio of the sieve size that will pass 60 percent of the filter sand, to the effective size.

Unihead
A casinghead unit capable of hanging multiple casing strings.

Uninterruptable Power Source
A power source which is utilized as a protective, continuous power supply of unwavering quality for electronic control equipment and/or computers when interruptions in power could be detrimental to the equipment being protected. Abbreviation: UPS.

Union
A coupling device used to connect pipe without the need to rotate the pipe. The makeup is accomplished by a flanged, threaded collar on the union.

Unique Well Identifier
The API well number for projects within the United States or an international code associated with the well referenced in the segment.

Unit
A combination of leases, or portions thereof, usually contiguous, involving potential or producing mineral properties for the purpose of efficient or economic operation.

Unit Abandoment Flag
Indicates the abandonment or termination of the operator's unit.

Unit Acreage
The acreage as described in a unit agreement as constituting the land logically subject to development under such an agreement.

Unit Agreement
An agreement for the recovery of oil and gas, where acreage is treated for operational purposes and for the allocation of costs and benefits as a single consolidated unit without regard to separate ownerships.

Unit Agreement Effective Date
The effective date of the Unit Agreement.

Unit Agreement Flag
An indicator of whether a wellbore is in a unit that has a unit agreement.

Unit Agreement Name
Name assigned by a regulatory agency to a unit.

Unit Agreement Number
The identifier assigned to an approved unit agreement.

Unit Agreement Type
The identifier for the type of unit agreement.

Unit Allocation Basis Code
The indicator of the method used to determine the percent lease allocation or the percent lease total participation.

Unit Angle
SEE: Inclinometer.

Unit Completion Flag
Identifies whether well completions are in a unit agreement.

Unit Field
A combination of lease parcels, usually contiguous, involving potential or producing mineral properties into a field. It is created for the purpose of efficient or economical operation by a unitization agreement.

Unit Identifier
A letter assignment of the quarter/quarter sections "A" through "P" and is used to designate the location of a well.

Unit Of Measure Code
A code specifying the units in which a value is being expressed or manner in which a measurement has been taken.

Unit- Of- Measurement System Code
A n indicator of the measurement system used throughout the Authorizatrion for Expenditure (AFE); e.g., U.S., Canadian, metric, etc.

Unit Operator
The company designated to operate unitized properties.

Unit Participating Acreage
The total surface area that is participating and receiving an allocation from unit production.

Unit Termination Date
The date that a unitization agreement is terminated.

Unit To Tract Participation Decimal
The portion that represents a tract's participation in the allocation of production (volume and possibly value) to the tract from a unit.

Unit Tract Number
The number assigned that uniquely identifies the parcel of land, lease, or portion of a lease in a unitization agreement.

Unitization
The combined operation of lease interests for the purposes of: (1) Accomplishing cooperative development and operation of oil and gas properties when the primary purpose is to attain maximum production, without waste, and with due regard to the protection of correlative rights.(2) Complying with well spacing requirements of Federal and state regulatory bodies.

Univalent
Monovalent.

Universal Transverse Mercator
A system for representing a portion of the curved surface of the earth upon a plane surface. Commonly abbreviated: UTM.

Universal Transverse Mercator Coordinate Location
The Universal Transverse Mercator (UTM) is one of the systems available for representing a portion of the curved surface of the earth upon a plane surface. Positions are defined in terms of plane-rectangular grid (x-y) coordinates. The grid system is designed for the expression of location between 80 degrees South latitude and 84 degrees North latitude.

Universal Transverse Mercator Method Code
An indicator of the values and matching descriptions which specify parameters used in the calculation of Universal Transverse Mercator (UTM) distance.

Universal Transverse Mercator Quadrangle
A description of location using quadrangle subdivisions of UTM zones.

Unload The Hole
To remove drilling fluid, water or other fluid from the wellbore to induce production.

Unmanned Platform
A platform where persons may be employed at any one time, but has no living accommodations or quarters.

Unmet Offset Well
Any producing well that: (1) Under specific provisions of an offsetting lease agreement, or existing spacing order, constitutes a direct or diagonal offset.(2) Is near enough to company acreage to indicate the possibility that company acreage, independent of whether the acreage is held by production or not, will suffer drainage if the well is not offset.(3) Is near enough to company acreage to qualify as an unmet offset well, but on the basis of prior or preliminary information, indications are tha

Unproved Reserves
Unproved reserves are based on geologic and/or engineering data similar to that used in estimates of proved reserves; but technical, contractual, economic, or regulatory uncertainties preclude such reserves being classified as proved.

Unusual Drilling Circumstances Encountered Flag
An indicator that out of the ordinary circumstances were encountered during the drilling.

Update Action Code
An indicator of whether information should be added, deleted, or modified.

Updip Well
A well having its wellbore penetrating a reservoir higher on a geologic structure than nearby wells do.

Upper Deck
Upper or roof deck level consisting of girder, beam and plate elements.

Upperstructure
SEE: Revolving Upperstructure.

Ups
SEE: Uninterruptable Power Source.

Upset
A forged metal pipe end with increased wall thickness and diameter used for threading or welding.

Upset Tubing
Tubing with a thicker wall and larger outside diameter on both ends of a joint to compensate for cutting the threads.

Upset Underfill
A depression on the outside or inside surface of an upset caused by insufficient flow of metal to completely fill out the upset to the desired shape.

Upset Wrinkles
A surface irregularity occurring on pipe upsets in the form of transverse forging lips.

Upstream Pipeline
The first pipeline to transport natural gas enroute to an interconnect point for delivery to another pipeline.

Upthrown Side
Side of a fault which appears to have moved upward relative to the other side, the downthrown side.

Upthrown Side Of Fault Formation Name
The formation penetrated by the wellbore on the upthrown side and adjacent to the fault plane.

Upturned Fiber Imperfection
SEE: Hook Crack.

Us Offshore Location Survey System
Subdivision of water bodies in the jurisdiction of U.S. federal and certain Gulf Coast states.

Us Township Range Section Survey System
A rectilinear system used to locate a block of land in the U.S. Used with Congressional or Jeffersonian type surveys.

Uscg
United States Coast Guard.

Usgs
United States Geological Survey, Department of the Interior.

Usgs Formation Code
An indicator of the formation name (assigned by the United States Geological Survey (USGS) ).

Utm
SEE: Universal Transverse Mercator.

Utm Coordinate Location
SEE: Universal Transverse Mercator Coordinate Location.

Utm Method Code
SEE: Universal Transverse Mercator Method Code.

Utm Quadrangle
SEE: Universal Transverse Mercator Quadrangle.